The Third Generation Partnership Project (3GPP) has developed a series of standardized specifications describing mechanisms for allowing aggregation of data from carriers located in the same or different frequency bands. The solution developed by 3GPP has two important limitations: the cells on the different frequencies to be aggregated must be collocated; and new terminals have to be developed so that they support each new aggregation capability developed.
The deployment of different frequency layers in the network is such that that collocation cannot always be guaranteed. For example, when aggregating cells from the 900 MHz and 2100 MHz bands (both bands being used by the Third Generation—3G—radio technology, UMTS), there are many scenarios where a user in coverage of the 900 MHz band can also be in coverage of a 2100 MHz cell which is not collocated (especially when 900 MHz is deployed as a coverage complement to 2100 MHz). Moreover, there will be so many different aggregation scenarios across bands and technologies that it will be difficult to secure support for all scenarios in terminals.
Likewise Multicarrier HSPA and LTE Carrier Aggregation (LTE-Advanced) are standardized, but time to market of new terminals capable of supporting such standards is long and frequency support can lead to a fragmented terminal “ecosystem”.
Thus, there is a need for a facility for aggregating different carriers within the same technology, or carriers from a number of different technologies, using existing terminals without mandating dedicated terminals requiring specific development from chipset vendors.